Christian Glass, 22, was shot five times by police after he made an emergency call for assistance from his car during an apparent mental health crisis.
Colorado news agency CPR News reports former Sheriff Deputy Andrew Buen has been sentenced to the maximum three years, after earlier being found guilty of criminally negligent homicide.
Before the sentencing there was more than an hour of tear-filled impact statements from Glass' mother, father and sister, along with Buen's family and friends.
Christian was born in Christchurch but his parents Simon and Sally relocated to Boulder, Colorado, when he was 10.
Simon Glass told the court his son's murder had torn up his life.
Last year another officer, Kyle Gould, also pleaded guilty to charges of criminally negligent homicide and reckless endangerment relating to the death.
He was fined NZ$1700 and given two years' probation.
